Ceiling construction



Aug. 11, 1953 v. JAcoBsoN 2,648,102

CEILING CONSTRUCTION Filed Nov. 3. 1950 2 Sheets-Sheet l ATTO R N EY5Aug. 1l, 1953 v. JAcoBsoN CEILING CONSTRUCTION 2 Sheets-Sheet 2 FiledNOV. C5, 1950 FIG. 2

INVENTOR for c/amsar/ ATTORNEYS Patented Aug. 11, 1953 CEILINGCONSTRUCTION Victor Jacobson, New Rochelle, N. Y., assignor toLevel-Line Ceilings Inc., New York, N. Y., a

corporation of New York Application November 3, 1950, Serial No. 193,827

4 Claims. l

IIlhis invention relates to acoustic corrective ceilings and has for itsobject the provision of an improved ceiling of this character. Moreparticularly, the invention provides a ceiling combination comprisingalternate rows of sound reflective and sound absorptive members. Theprincipal feature of the invention is that the relative Widths of theexposed surfaces of the sound reflecting and sound absorptive membersare in such proportions or ratios that the ceiling has improved acousticcorrective characteristics. The sound reflective members are thin metalmembers supported from above and the sound absorptive members are in theform of acoustical tile in edge contact with the sound reflectivemembers.

In its more complete and preferred embodiment, the acoustic ceiling ofthe invention comprises reilective members formed of thin sheet metaleach having a flat web portion, and absorptive members formed ofacoustical tile, the total under surfaces of which comprise asubstantial part of the exposed surface of the ceiling. The soundreflective members are constructed and arranged 4to function bydiaphragmatic action caused by the impingement of the sound Wavesthereon, and the absorptive members are formed of a porous or cellularmaterial which dissipates the sound by the friction the material offersto the sound waves which enter or penetrate the material.

The reflective members and absorptive members are suspended in alternateadjoining rows of any desired length. I have discovered, however, thatwhen the widths of the members are in a critical relationship, theceiling has improved acoustic corrective properties. This critical Widthrelationship is advantageously expressible in terms of ratios and tothis end the acoustic corrective ceiling of my invention has ratios ofreflective member width to absorptive member width varying from 1 to 2to 1 to 8.

These and other objects of the invention will be better understood afterconsidering the following discussion taken in conjunction with theaccompanying drawings, in which:

Fig. 1 is a perspective view of part of a ceiling embodying theinvention; f

Fig. 2 is a sectional View at 2--2 of Fig. 1;

Fig. 3 is a perspective View of the connection of two abutting soundreflective members, and

Fig. 4 is a sectional view similar to Fig. 2 of another embodiment ofthe invention.

The embodiment of the invention illustrated in Fig. 1 comprises achannel bar I which is a primary. ceiling supporting member connected tothe building by means commonly used. Any number of similar or equivalentmembers may be used and in any constructional arrangement to support theceiling members of my invention. The ceiling of my invention comprisessound reective members 2 formed of any suitable metal and of suchthinness that they have diaphragmatic action. When the member is made ofa metal such as steel or aluminum, the thickness may vary from 0.019 to0.025 inch. Should this thickness become greater than 0.025` inch, thediaphragmatic action would be lost from this member. 'IIhe metal isfolded upon itself to form the longitudinal ribs or shelves 3 and 4 andthe fiat interconnecting web portion 5 inside these shelves is thefreely vibratory portion which is the effective width of the soundreflective member. From the shelves the metal is turned upwardly,preferably at right angles, to form the ilanges 6 and l and the upperedge portions of the flanges are ben-t inwardly and downwardly to formthe channels 8 and 9 for receiving the hooks I0 of the hangers I2. 'Iheextreme edges are preferably given additional curved bends I3 and I4 toimpart stiffness. The width a of the web 5 of the sound reflectivemember is the distance between the fianges 6 and l excluding therelatively stiff non-vibratory metal of the ribs or shelves 3 and 4, andis the width measure of the sound reflective member used in the ratios.The sound reflective members have flat under surfaces in the ceilingarea the width b.

Where the ceiling proportions require the reflective members to bejoined end-for-end, I provide a splicer I6, Fig. 3, in the general formof a channel having a web I1, side flanges I8 and I9, and edge breaks 20and 2| which elect a snug engagement with the channels 8 and 9. 'Iheupwardly pressed tabs 22 and 23 facilitate sliding the splicer intoposition. A ceiling construction employing sound reflective members asshown in Figs. 1 to 3 is claimed in my copending application Serial No.58,439, led November 5, 1948, of which this appli-cation is acontinuation-in-part.

The sound absorptive member 30 is in the form of relatively thick, say,l inch to 11/2 inches, slabs or tiles of a cellular or porous material.Acoustic corrective material has been widely used heretofore forceilings and walls, said material for best advantages being cheaply andsatisfactorily formed in sheets or tiles of more or less looselycompacted bers of vegetable or other material, having myriads ofirregular cells, interstices, or openings communicating with theexterior surfaces, into which cells or openings sound waves may enterand be substantially completely absorbed through friction so that thesound waves will become dissipated, thereby rendering a room extremelyquiet as compared to a room, the ceiling and walls of which are of densematerial. In some instances the exposed surface portion of the tiles ofacoustical material has been purposely provided with mechanicallydrilled relatively large openings or cells for better penetration andentrapment of the sound waves therein. It is to be understood that, acecording to this invention, there may be employed any satisfactoryacoustical material which has the characteristic of frictionallyabsorbing sound Waves, though preferably such acoustical material shouldbe formed in sheets or tiles of rela.- tive rigidity for ease inhandling and applying to the ceiling. One satisfactory type of materialis sold under the name of Acousti-Celotex.

Absorptive tile of a type readily available for -this and other uses isprovided with edge slots 3l and cut-back edge portions 32 to facilitatethe use of connecting splines or brackets. These slots and cut-backsserve no useful purposes along those edges which engage the edge flangesB and 1 of the reflective members but where one tile joins another, asin Fig. 1, connecting splines 33 are used to hold the edges in evenContact.

A ceiling construction, as illustrated in Figs. 1 and 2, comprisesalternate rows of reflective members 2 and absorptive members 30, theabsorptive members being in edge contact with the reflective members andsupported on the shelves 3 and 4. The under surfaces of the reflectiveand absorptive members form the major or entire ceiling area. Theflanges 3 and 4 may be, say, inch Wide, and to that extent cover theedges of the absorptive tiles. However, in view of the dissipation ofsound energy in the porous material the width of absorptive members, asmentioned herein, is the full width c from edge to edge, notwithstandingthe apparent shielding by the shelves 3 and 4.

Acoustic ceilings constructed according to the invention comprise soundreflective members which are relatively narrow, say, from 6 to 12 inchesin width, and sound absorptive members which are relatively wider, say,from 12 to 48 inches. 6 to 12 inches or 12 to 24 inches, the perform-vance would be 65% noise reduction coefilcient (N. R. 0.). When therespective width ratios are 6 to 24 inches or 12 to 4 8 inches, theperformance of the ceiling becomes r70% N. R.. C. When the reflectivemember is 6 inches and the absorptive member is 12 inches, the ratio is1 to 2, and when the reflective member is 6 inches and the absorptivemember is 48 inches, the ratio is 1 to 8. The range of ratios of theinvention is from l to 2 to 1 to 8, including the intermediate ratios.Such intermediate ratios would be exemf pliiied in a ceiling with asound reflective mem. ber of 12 inches and an absorptive member of 36inches or a sound reflective member of 6 inches and an absorptive memberof 24 inches, etc.

By way of illustrating the effectiveness, con.- structional andcommercial advantages of the invention, the following comparisons areinter-- esting. If a ceiling were constructed with a continuous sheet ofthe sound absorptive material, it might have, for example, a N. R. C.of, say, '75%. By means of the construction of the invention, the areaof the sound absorptive material may be diminished by, say, as much as20% When the respective width ratios are by using the sound reflectivemembers without sacrificing to any noticeable degree the N. R. C.Specifically, this very material diminution in area of sound absorptivematerial gives the practical equivalent sound characteristics.Notwithstanding the 20% decrease in the area thereof, the N. R. C. isreduced merely to about '70%. It must be noted, however, that it isessential to have an alternate arrangement whereby the respective areasare distributed and not concentrated at one particular place.

The metal members 2 have been described as sound reflective members forpractical purposes in correcting objectionable noises which havefrequencies largely in the reflective range. Actually, the members arereflective in the higher frequencies which are found in most noisysounds, but absorptive in the very low frequencies such as the low notesof musical instruments. It is to be understood, therefore, that themetal member is reflective in the practical sense for correcting noises.

The embodiment of the invention illustrated in Fig. 4 is similar in allrespects to the ceiling of Figs. 1 and 2, with the exception that thesound reflective members 4U have ribs or shelves 4I and 42 which arespaced above the bottom of the web 43. These shelves are positioned andproportioned to enter the slots 3| of the absorptive tiles 30 andsupport them in position with their under surfaces even with the websurfaces 43. In this form of the invention the beveled edge 44 gives adecorative aspect to the ceiling.

I claim:

1. An acoustic corrective ceiling construction comprising soundreflective members formed of thin metal having freely vibratory webportions and sound absorptive members in the form of tiles of cellularmaterial, said members being arranged in side-by-side adjoining relationand the under surfaces of the web portions and the under surfaces of thesound absorptive members being flat and forming substantially the entireceiling surface, the web portions of the sound reflective members beingof such thickness and having such width that they have daphragmaticaction upon impingement of sound waves of noise frequency thereon, theratios of the widths of the sound reflective members to the Soundabsorptive members being from 1 to 2 to l to 8.

2. An acoustic ceiling according to claim 1 in which the soundabsorptive members are flat tiles varying in thickness from 1/ inch to11/2 inches.

3. An acoustic corrective ceiling according to claim 1 in which thethickness of the web portion varies from 0.019 to 0.025 inch and isfreely vibratory.

4. An acoustic ceiling according to claim 1 in which the soundreflective members are suspended from above and the sound absorptivemembers are supported at the edge portions thereof by the soundreflective members.

VICTOR JACOBSON.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,099,211 Lucius Nov. 16, 1937 2,161,708 Heerwagen June 6,1939 2,221,001 Lucius Nov. 12, 1940 2,270,268 Chambers Jan. 20, 19422,308,869 Eckardt Jan. 19, 1943 FOREIGN PATENTS Number Country Date495,755 Great Britain Nov. 16, 193.8

